Variation of global diurnal temperature range associated with the Madden-Julian Oscillation

Abstract

This study examines the impact of the intraseasonal Madden-Julian Oscillation (MJO) on global land surface diurnal temperature range (DTR) using two daily surface air temperature datasets. The results show that the MJO significantly affects DTR over all the continents. The two datasets are highly consistent with each other, suggesting that the results are robust. Significant correlations exist in all seasons over the tropical continents, including Africa, India, southeast Asia, Australia, central America and Amazon. In the extratropics, the correlations change with season. The highest correlations occur in winter for Europe, in winter and spring for China, in autumn for United States, and in summer and winter for Canada. The surface DTR anomalies coincide well with the outgoing longwave radiation (OLR) anomalies at the top of the atmosphere, suggesting that variations of DTR are associated with variations of clouds, which is consistent with the results of previous studies on DTR trend and variability at seasonal to multi-decadal time-scales. The DTR variations are also associated with changes of deep convection, soil moisture and snow cover.